Catheter

ABSTRACT

A catheter that prevents excessive concentration of stress while providing sufficient flexibility to a distal end portion of the catheter, even when the catheter is inserted and curved in patient&#39;s a blood vessel. Thus, breakage of the catheter at a radiopaque marker is prevented/reduced. The catheter includes a catheter tube and the radiopaque marker, which is disposed in the catheter tube. The radiopaque marker is fixed in the catheter so that a gap is provided between the radiopaque marker and the catheter tube in a radial direction of the catheter tube.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority to Japanese Patent Application No.2015-242283, filed in the Japan Patent Office on Dec. 11, 2015, andJapanese Patent Application No. 2015-026948, filed in the Japan PatentOffice on Feb. 13, 2015, the entire contents of which are incorporatedby reference.

BACKGROUND

The disclosed embodiments relate to a catheter for medical use.

Conventional balloon catheters include a radiopaque marker at a distalend of the catheter so that a distal end position of the catheter can bevisually observed during procedures.

For example, Patent Literature 1 (identified below) discloses a catheterincluding an elongate main tubular body 10 with apolytetrafluoroethylene core 16 and a polyurethane outer jacket 18,which covers the polytetrafluoroethylene core 16. Additionally, thecatheter includes a soft pointed tip 12 adhered to a distal end of themain tubular body 10, and a radiopaque precious metal marker band 14 isprovided at a portion where the main tubular body 10 and the softpointed tip 12 are connected to each other (see the upper right columnin page 5, FIG. 1, etc.).

Patent Literature 2 (identified below) discloses a catheter tube formedical use that includes a resin inner layer tube, a reinforcingmaterial layer that is wound around the periphery of the inner layertube, and an outer layer tube that covers the inner layer tube and thereinforcing material layer. Additionally, the catheter tube includes anX-ray impermeable marker that is arranged to be in contact with thereinforcing material layer (see FIG. 20, etc.).

PATENT LITERATURE

Patent Literature 1: Japanese Patent Application Laid-open No. S64-68276

Patent Literature 2: Japanese Patent Application Laid-open No.2006-34347

SUMMARY

However, the above-described conventional catheters, including thecatheters of Patent Literature 1 and Patent Literature 2, have a problemin that the rigidity is much higher in the region where the radiopaquemarker is provided than the rigidity of other regions.

To be more specific, the distal end portion of the conventionalcatheters are formed of resin having high flexibility to facilitateinsertion of the catheters into a patient's body. However, when aradiopaque marker formed of metal materials, such as platinum, isprovided at the distal end portion of the catheter, the rigidity of thedistal end portion becomes higher. This causes a break in rigidity at aborder area between the portion where the radiopaque marker is providedand a portion where the radiopaque marker is not provided. Therefore,when a technician operates the conventional catheters such that thecatheters are curved repeatedly in a patient's body, for example, stressis excessively concentrated at the border area between the portion wherethe radiopaque marker is provided and the portion where the radiopaquemarker is not provided, causing a problem that the catheters are easilybroken at such a border area.

Thus, the present disclosure provides a catheter with a radiopaquemarker and that prevents excessive concentration of stress whileproviding sufficient flexibility to a distal end portion of thecatheter, even when the catheter is inserted and curved in a bloodvessel. Thus, a break in the catheter due to the radiopaque marker isprevented/reduced.

The disclosed embodiments include a catheter having a tubular bodyincluding an inner layer and a distal end outer layer and a ring-formedradiopaque marker disposed in the tubular body, the ring-formedradiopaque marker is disposed between the inner layer and a radiallyouter portion of the distal end outer layer. A first gap including emptyspace is provided between the radiopaque marker and the tubular body ina radial direction of the tubular body, the first gap being formedbetween a radially inner side of the ring-formed radiopaque marker andthe inner layer. A radially inner portion of the distal end outer layerpartially enters the first gap so that the distal end outer layerextends partialy between the ring-formed radiopaque marker and the innerlayer.

In the disclosed embodiments, even when the catheter is inserted andcurved in a patient's blood vessel, it is possible to prevent excessiveconcentration of stress while providing sufficient flexibility to thedistal end portion of the catheter. Thus, the disclosed embodimentsprevent/reduce breaking of the catheter.

In some embodiments, a second gap is provided on a radially outer sideof the radiopaque marker in the radial direction of the tubular body.

In some embodiments, a reinforcing member is disposed in the tubularbody such that the reinforcing member extends along a longitudinal axisof the tubular body, the radiopaque marker being fixed to a distal endof the reinforcing member.

In some embodiments, the gap extends at the distal end of thereinforcing member to which the radiopaque marker is fixed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a catheter according to the disclosedembodiments.

FIG. 2 is a partial enlarged section of the catheter of FIG. 1.according to the disclosed embodiments.

FIG. 3 is a partial enlarged section of the catheter of FIG. 1 accordingto the disclosed embodiments.

FIG. 4 is a partial enlarged section of the catheter of FIG. 1 accordingto the disclosed embodiments.

FIG. 5 is a partial enlarged section of the catheter of FIG. 1 accordingto the disclosed embodiments.

FIG. 6 is a partial enlarged section of the catheter of FIG. 1 accordingto the disclosed embodiments.

DETAILED DESCRIPTION OF EMBODIMENTS

The catheter according to the disclosed embodiments will be describedwith reference to the enclosed drawings. The present disclosure shallnot be limited to the embodiments provided below, and modifications indesign can appropriately be made.

FIG. 1 is a plan view of a catheter according to embodiments of thepresent disclosure, and FIG. 2 is a partial enlarged section of thecatheter of FIG. 1.

As illustrated in FIG. 1, catheter 1 includes an operation part 10,which is operated by a technician, and a catheter tube 20 (correspondingto a “tubular body”), which is connected to a distal end of theoperation part 10. Moreover, the catheter tube 20 includes a cathetermain body part 21, extending from the operation part 10, and a distalend tip 22, positioned on the distal end side of the catheter main bodypart 21. Each of the vicinity of the distal end of the catheter mainbody part 21 and the vicinity of the distal end of the distal end tip 22has a tapered form in which the outer diameter becomes smaller towardthe distal end.

Moreover, as illustrated in FIG. 2, the catheter main body part 21 has amultilayer structure, and includes an inner layer 24, a braid 25, and anouter layer 26 in the order from the inner side in a radial directionrelative to a center axis of the catheter main body part 21.

The inner layer 24 has a tubular form with a lumen 23, and the innerlayer 24 extends along the catheter main body 21 and along the distalend tip 22. The inner layer 24 is preferably formed of a fluororesin,such as polytetrafluoroethylene, having small sliding resistance.Moreover, the inner layer 24 may have a multilayer structure partiallyor entirely along its length.

The braid 25 is arranged at the periphery of the inner layer 24. Thedistal end of the braid 25 is arranged in the distal end tip 22, and thedistal end of the braid 25 is proximal of the distal end of the innerlayer 24. The braid 25 may be formed of a plurality of pieces of elementwire arranged at the periphery of the inner layer 24. Alternatively, thebraid 25 may be formed of a coil wound by a single piece or a pluralityof pieces of element wire. The braid 25 may be formed of materials suchas, for example, stainless steel, superelastic alloy such as an Ni—Tialloy, piano wire, or tungsten wire.

The outer layer 26 is arranged to cover the periphery of the inner layer24 and the braid 25. As shown in FIG. 2, the distal end of the outerlayer 26 forms the distal end of the catheter main body part 21. Areinforcing member 27, formed of a coil, may be arranged in the outerlayer 26 such that the reinforcing member 27 is coaxial with the outerlayer 26. Thus, the reinforcing member 27 and the outer layer 26 form areinforcing layer 28. As shown in FIG. 2, the distal end of thereinforcing member 27 may extend to the distal end of the catheter mainbody part 21. In the embodiment of FIG. 2, a coil is used as thereinforcing member 27. However, a braid formed by braiding a pluralityof pieces of element wire may be used. The reinforcing member 27 isfarmed of materials such as, for example, stainless steel, superelasticalloy such as an Ni—Ti alloy, piano wire, or tungsten wire.

The resin materials forming the outer layer 26 may include polyamide,polyamide elastomer, polyester, polyurethane, or the like, for example.In the embodiment of FIG. 2, polyurethane is used. Moreover, the outerlayer 26 may have a multilayer structure partially or entirely along itslength.

The distal end tip 22 has a multilayer structure, and includes, from theinner side in a radial direction relative to a center axis line of thedistal end tip 22, the inner layer 24, the braid 25, and a distal endouter layer 29. The distal end outer layer 29 may be formed continuouslyfrom the outer layer 26. The resin materials forming the distal endouter layer 29 may include polyamide, polyamide elastomer, polyester,polyurethane, or the like, for example, similar to the outer layer 26.In the embodiment of FIG. 2, polyurethane is used for the distal endouter layer 29. Thus, the main part of the distal end tip 22 is formedof polyurethane (or the other resin materials disclosed herein) anddamage to a patient's blood vessel inner walls can be prevented. Inorder to improve the visibility of the distal end tip 22, the distal endouter layer 29 preferably contains radiopaque tungsten powder, and thelike.

A ring-formed radiopaque marker 30 formed of a platinum material isarranged in the distal end tip 22. The proximal end of the radiopaquemarker 30 is fixed to the distal end of the reinforcing member 27through a fused part 30 a. For example, the proximal end of theradiopaque marker 30 and the distal end of the reinforcing member 27 arefused together by YAG welding. In the disclosed embodiments, platinum isused for the radiopaque marker 30. However, other well-known radiopaquemetal materials may be used. As shown in FIG. 2, the proximal end of theradiopaque marker 30 and the distal end of the reinforcing member 27 arefused together. However, they may be fixed to each other by otherwell-known fixing methods, such as an adhesive.

A gap 35 is provided between the inner layer 24 and the radiopaquemarker 30 on the inner side in a radial direction of the catheter tube20. A part of the inner peripheral surface of the radiopaque marker 30is exposed to the gap 35. That is, an inner peripheral surface of theradiopaque marker 30 that faces the inner layer 24 is not in contactwith other members.

In the catheter 1, the radiopaque marker 30 is fixed so that the gap 35is provided between the radiopaque marker 30 and the inner layer 24 onthe inner side in a radial direction of the catheter tube 20. Thus, evenwhen the catheter 1 is inserted and curved in a blood vessel, the gap 35can sufficiently absorb deformation of the inner layer 24, the distalend outer layer 29, and the like around the radiopaque marker 30. Thus,the gap 35 can prevent excessive concentration of stress. In thismanner, it is possible to provide sufficient flexibility to the distalend portion of the catheter 1 while preventing/reducing a break of thecatheter 1 at the location (vicinity) of the radiopaque marker 30.

Furthermore, as described above, the radiopaque marker 30 is fused withthe distal end of the reinforcing member 27. Thus, it is possible toprevent displacement of the radiopaque marker 30 and excessiveconcentration of stress. Accordingly, breakage of the catheter at thelocation (vicinity) of the radiopaque marker 30 is prevented/reduced.Moreover, in the process for manufacturing the catheter tube 20, thedistal end outer layer 29 can be formed in the state where theradiopaque marker 30 is fused with the distal end of the reinforcingmember 27. Thus, it is possible to prevent displacement of theradiopaque marker 30 and to produce the catheter 1 with high dimensionalaccuracy.

Furthermore, the reinforcing member 27 and the radiopaque marker 30 arefused with each other so that the resin material forming the distal endouter layer 29 does not enter the gap 35. Thus, it is possible to formthe gap 35 easily.

Moreover, the gap 35 is also formed between the fused part 30 a (distalend of the reinforcing member 27) and the inner layer 24. Thus, when thecatheter 1 is inserted and curved in a patient's blood vessel, it ispossible to further prevent excessive concentration of stress. Thus, thedistal end portion of the catheter 1 may have sufficient flexibilitywhile preventing/reducing a break of the catheter at the location(vicinity) of the radiopaque marker 30.

FIG. 3 is a partial enlarged section illustrating a modification of thecatheter of FIG. 2. In FIG. 3, the distal end outer layer 29 partiallyenters the gap 35 provided between the radiopaque marker 30 and theinner layer 24. Thus, the distal end outer layer 29 extends partiallybetween the radiopaque marker 30 and the inner layer 24. In such aconfiguration, the radiopaque marker 30 is fused with the reinforcingmember 27 through the fused part 30 a. Additionally, the lower side(inner side) of the radiopaque marker 30 is supported by the distal endouter layer 29. Thus, displacement of the radiopaque marker 30 isfurther prevented.

As discussed above, the radiopaque marker 30 and the gap 35 are arrangedin the tubular body 20 so that the radiopaque marker 30 is fixed in aradial direction of the tubular body 20.

FIG. 4 is a partial enlarged section illustrating a modification of thecatheter of FIG. 2. The parts common to the catheter according to theembodiment of FIG. 2 will be represented with the same symbols in thedrawings, and the explanation thereof will be simplified or omitted.

In FIG. 4, catheter tube 50 is different from the catheter tube 20 ofFIG. 2 in the positional relation between the radiopaque marker and thegap.

Similar to FIG. 2, a radiopaque marker 60 is arranged on the distal endtip 22 such that a proximal end of the radiopaque marker 60 is fusedwith a distal end of a reinforcing member 57 through a fused part 60 a.Additionally, the outer layer 26 and the reinforcing member 57 form areinforcing layer 58. Distinct from FIG. 2, a gap 65 is arranged on theouter side in a radial direction of the catheter tube 50 relative to theradiopaque marker 60 (between the radiopaque marker 60 and a distal endouter layer 59).

In such a configuration, when the catheter of FIG. 4 is inserted andcurved in a patient's blood vessel, it is possible to prevent excessiveconcentration of stress and to provide sufficient flexibility to thedistal end portion of the catheter 1. Thus, it is possible toprevent/reduce a break of the catheter 1 at the location (vicinity) ofthe radiopaque marker 60. Moreover, the gap 65 is also formed betweenthe fused part 60 a (distal end of the reinforcing member 57) and thedistal end outer layer 59. Thus, when the catheter is inserted andcurved in a patient's blood vessel, it is possible to further preventexcessive concentration of stress and to provide sufficient flexibilityto the distal end portion of the catheter. Thus, it is possible tofurther prevent/reduce a break of the catheter 1 at the location(vicinity) of the radiopaque marker 60.

FIG. 5 is a partial enlarged section illustrating a modification of thecatheter of FIG. 2. The parts common to the catheter according to FIG. 2will be represented with the same symbols in the drawings, and theexplanation thereof will be simplified or omitted.

In FIG. 5, catheter tube 70 is different from the catheter tube 20 ofFIG. 2 in the positional relation between the radiopaque marker and thegap.

Similar to FIG. 2, a radiopaque marker 80 is arranged at the distal endtip 22 such that a proximal end of the radiopaque marker 80 is fusedwith a distal end of a reinforcing member 77 through a fused part 80 a.Additionally, the outer layer 26 and the reinforcing member 77 form areinforcing layer 78. Distinct from FIG. 2, a gap 85 is arranged on theboth sides in a radial direction of the catheter tube 70 relative to theradiopaque marker 80 (between the radiopaque marker 80 and the innerlayer 24 and between the radiopaque marker 80 and a distal end outerlayer 79).

In such a configuration, when the catheter of FIG. 5 is inserted andcurved in a patient's blood vessel, it is possible to further preventexcessive concentration of stress and to provide sufficient flexibilityto the distal end portion of the catheter. Thus, it is possible toprevent/reduce a break of the catheter 1 at the location (vicinity) ofthe radiopaque marker 80.

FIG. 6 is a partial enlarged section illustrating a modification of thecatheter of FIG. 2. The parts common to the catheter according to FIG. 2will be represented with the same symbols in the drawings, and theexplanation thereof will be simplified or omitted.

Similar to FIG. 2, catheter tube 90 includes the catheter main body part21 and the distal end tip 22. The catheter main body part 21 includes aninner layer 91 and an outer layer 92, covering the periphery of theinner layer 91. The distal end tip 22 includes the inner layer 91, whichextends from the catheter main body part 21, and a distal end outerlayer 93, which covers the periphery of the inner layer 91.

A radiopaque marker 94 is arranged at the distal end tip 22 between theinner layer 91 and the distal end outer layer 93. Additionally, a gap 95is provided between the radiopaque marker 94 and the inner layer 91.

In such a configuration, when the catheter is inserted and curved in apatient's blood vessel, it is possible, with the gap 95 on the innerside of the radiopaque marker 94, to prevent excessive concentration ofstress and to provide sufficient flexibility to the distal end portionof the catheter 1. Thus, it is possible to prevent/reduce a break of thecatheter 1 at the location (vicinity) of the radiopaque marker 94.

The gap 95 is provided between the radiopaque marker 94 and the innerlayer 91. However, similarly to the catheters discussed above, the gap95 may be provided on the outer side in a radial direction of thecatheter tube 90 relative to the radiopaque marker 94 (between theradiopaque marker 94 and the distal end outer layer 93) or on the bothsides in a radial direction of the catheter tube 90 relative to theradiopaque marker 94 (between the radiopaque marker 94 and the innerlayer 91 and between the radiopaque marker 94 and the distal end outerlayer 93). Also in such cases, the same effect as the effect describedin each embodiment is exerted.

As discussed above, the radiopaque marker may be arranged at the distalend tip 22. Additionally or alternatively, the radiopaque marker may bearranged at the catheter tube 20/50/70/90. In such a case, the sameeffect as the effect described in each embodiment is exerted.

In some embodiments, the catheter tube 20/50/70/90 and the distal endtip 22 may be formed integrally with each other. In such a case, thesame effect as the effect described in each embodiment is exerted.

In the embodiments discussed above, the radiopaque marker has a ringshape. However, the shape of the radiopaque marker may be other shapessuch as, for example, a coil shape or a ring shape with a partialcutout.

What is claimed is:
 1. A catheter, comprising: a tubular body includingan inner layer and a distal end outer layer; and a ring-formedradiopaque marker disposed in the tubular body, wherein the ring-formedradiopaque marker is disposed between the inner layer and a radiallyouter portion of the distal end outer layer, a first gap including anempty space is formed between a radially inner side of the ring-formedradiopaque marker and the inner layer, and a radially inner portion ofthe distal end outer layer partially enters the first gap so that thedistal end outer layer extends partially between the ring-formedradiopaque marker and the inner layer.
 2. The catheter according toclaim 1, wherein a second gap is provided on a radially outer side ofthe ring-formed radiopaque marker.